This invention relates to the splice enclosure arts and more specifically to an apparatus and method for sealing splice enclosures.
Dependency upon telecommunications and data communications presses the technology to provide consistent high quality communications with minimal down time. A key to providing high quality communications with minimal down time is to protect installations at critical points and provide for quick and efficient in-field repairs.
In the communications field it is common to install multi-carrier primary cables to provide communication service to a predetermined area. The primary cable, consists of perhaps approximately 100 individual binder groups of multiple wire pairs.
At specific points along the primary cable, connections must be made to route individual wire pairs to end user locations. Primary cables are typically very long continuous cables and are not conveniently manufacturable with specific service cable lengths at predetermined break off points. In this situation, it becomes necessary to extract specific binder groups from the primary cables and to splice these wire pairs to service cables which are then routed to the end user locations.
The splice connection between the service cable and the primary cable wire pairs must be protected from the environment in which it is installed, since moisture, oxygen, temperature, and the accumulation of dust and dirt or chemicals may individually or cumulatively act to the detriment of the splice connections. Typically, prior art splice encloses protects a portion of primary cable and the splice connections in a so-called dome enclosure. The dome enclosure is an elongate sleeve-like structure having a closed end and an open end through which the primary cable and service cables are inserted and from which these cables project. To protect the primary cable and the splice connections from detrimental environmental effects, the open end of the dome enclosure must be sealed.
Current dome enclosure sealing technology has problems which must be overcome to improve telecommunications quality and minimize down time for repairs. For example, a typical prior art sealing arrangement which seals the opening formed in the dome enclosure must be individually fabricated for each installation which is to be sealed. The sealing arrangement is fabricated by repeatedly wrapping tape-like material around the cables projecting through the opening and then inserting the wrapped cables in the opening. The dome enclosure then employs some form of circumferential constricting apparatus to circumferentially compress the wrapped cables to enhance the seal.
This type of prior art sealing arrangement is complex and time consuming to assemble and unnecessarily lengthens down time for installations and repairs. The problem is exacerbated when a repair or modification is needed to the splice connections since under the circumstances the sealing arrangement must be severed and removed and a new sealing arrangement re-constructed. This type of prior art sealing arrangement and method unnecessarily wastes time and valuable resources.
A specific example of a prior art enclosure and sealing arrangement is the PST pedestal splice closure manufactured by 3M, TeleComm Products Division, Austin, Tex. This arrangement is also shown in U.S. Pat. No. 4,902,855 to Smith. In this prior art splice enclosure, the cables are inserted into a dome enclosure and the open end is sealed. A sealing arrangement is formed through the tape wrapping method described above. This method forms a seal which is inherently non-uniform thereby creating potential for problems with the fit inside of the dome member and/or any circumferential compression fitting or clamp used to engage and seal the structure. Further, depending upon the type of tape used, the ground wires may have to be separately wrapped prior to incorporation into the common seal. The sealing arrangement as formed is then inserted into the open end of the dome enclosure and a shrink tubing is positioned and shrunk around the outside of the dome to retain the sealing member therein. Alternately, a clamp may be used, as shown in the above-mentioned '855 patent.
As mentioned above, this type of prior art sealing system is inherently extremely time consuming and material intensive. Further, this system risks cutting or otherwise damaging cable jackets in attempting to remove the shrink tubing as well as the sealing member when repairing or modifying splice connections. Additionally, sufficient supplies such as tapes and shrink tubing must always be on hand or further delays due to lack of supplies may result when installing or repairing splice connections.